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lvconvert: add infrastructure for RaidLV reshaping support

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In order to support striped raid5/6/10 LV reshaping (change
of LV type, stripesize or number of legs), this patch
introduces more local infrastructure to raid_manip.c
used by followup patches.

Changes:
- add lv_raid_data_copies returning raid type specific number;
  needed for raid10 with more than 2 data copies
- remove _shift_and_rename_image_components() constraint
  to support more than 10 raid legs
- add function to calculate total rimage length used by out-of-place
  reshape space allocation
- add out-of-place reshape space alloc/relocate/free functions
- move _data_rimages_count() used by reshape space alloc/realocate functions

Related: rhbz834579
Related: rhbz1191935
Related: rhbz1191978
This commit is contained in:
Heinz Mauelshagen 2017-02-24 01:57:04 +01:00
parent c1865b0a86
commit 92691e345d
3 changed files with 443 additions and 31 deletions
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2
lib/metadata/lv_manip.c
View File

@ -957,7 +957,7 @@ struct lv_segment *alloc_lv_segment(const struct segment_type *segtype,
seg->stripe_size = stripe_size;
seg->area_count = area_count;
seg->area_len = area_len;
seg->data_copies = data_copies ? : 0; // lv_raid_data_copies(segtype, area_count);
seg->data_copies = data_copies ? : lv_raid_data_copies(segtype, area_count);
seg->chunk_size = chunk_size;
seg->region_size = region_size;
seg->extents_copied = extents_copied;

470
lib/metadata/raid_manip.c
View File

@ -708,12 +708,11 @@ static int _reorder_raid10_near_seg_areas(struct lv_segment *seg, enum raid0_rai
*
* Returns: 1 on success, 0 on failure
*/
static char *_generate_raid_name(struct logical_volume *lv,
const char *suffix, int count);
static int _shift_and_rename_image_components(struct lv_segment *seg)
{
int len;
char *shift_name;
uint32_t s, missing;
struct cmd_context *cmd = seg->lv->vg->cmd;
/*
* All LVs must be properly named for their index before
@ -724,21 +723,12 @@ static int _shift_and_rename_image_components(struct lv_segment *seg)
if (!seg_is_raid(seg))
return_0;
if (seg->area_count > 10) {
/*
* FIXME: Handling more would mean I'd have
* to handle double digits
*/
log_error("Unable handle arrays with more than 10 devices.");
return 0;
}
log_very_verbose("Shifting images in %s.", display_lvname(seg->lv));
for (s = 0, missing = 0; s < seg->area_count; s++) {
if (seg_type(seg, s) == AREA_UNASSIGNED) {
if (seg_metatype(seg, s) != AREA_UNASSIGNED) {
log_error(INTERNAL_ERROR "Metadata segment area"
log_error(INTERNAL_ERROR "Metadata segment area."
" #%d should be AREA_UNASSIGNED.", s);
return 0;
}
@ -753,24 +743,16 @@ static int _shift_and_rename_image_components(struct lv_segment *seg)
display_lvname(seg_lv(seg, s)), missing);
/* Alter rmeta name */
shift_name = dm_pool_strdup(cmd->mem, seg_metalv(seg, s)->name);
if (!shift_name) {
if (!(seg_metalv(seg, s)->name = _generate_raid_name(seg->lv, "rmeta", s - missing))) {
log_error("Memory allocation failed.");
return 0;
}
len = strlen(shift_name) - 1;
shift_name[len] -= missing;
seg_metalv(seg, s)->name = shift_name;
/* Alter rimage name */
shift_name = dm_pool_strdup(cmd->mem, seg_lv(seg, s)->name);
if (!shift_name) {
if (!(seg_lv(seg, s)->name = _generate_raid_name(seg->lv, "rimage", s - missing))) {
log_error("Memory allocation failed.");
return 0;
}
len = strlen(shift_name) - 1;
shift_name[len] -= missing;
seg_lv(seg, s)->name = shift_name;
seg->areas[s - missing] = seg->areas[s];
seg->meta_areas[s - missing] = seg->meta_areas[s];
@ -1030,6 +1012,442 @@ uint32_t raid_rimage_extents(const struct segment_type *segtype,
return r > UINT_MAX ? 0 : (uint32_t) r;
}
/* Return number of data copies for @segtype */
uint32_t lv_raid_data_copies(const struct segment_type *segtype, uint32_t area_count)
{
if (segtype_is_any_raid10(segtype))
/* FIXME: change for variable number of data copies */
return 2;
else if (segtype_is_mirrored(segtype))
return area_count;
else if (segtype_is_striped_raid(segtype))
return segtype->parity_devs + 1;
return 1;
}
/* Return data images count for @total_rimages depending on @seg's type */
static uint32_t _data_rimages_count(const struct lv_segment *seg, const uint32_t total_rimages)
{
if (!seg_is_thin(seg) && total_rimages <= seg->segtype->parity_devs)
return_0;
return total_rimages - seg->segtype->parity_devs;
}
/* Get total area len of @lv, i.e. sum of area_len of all segments */
static uint32_t _lv_total_rimage_len(struct logical_volume *lv)
{
uint32_t s;
struct lv_segment *seg = first_seg(lv);
if (seg_is_raid(seg)) {
for (s = 0; s < seg->area_count; s++)
if (seg_lv(seg, s))
return seg_lv(seg, s)->le_count;
} else
return lv->le_count;
return_0;
}
/*
* HM helper:
*
* Compare the raid levels in segtype @t1 and @t2
*
* Return 1 if same, else 0
*/
static int _cmp_level(const struct segment_type *t1, const struct segment_type *t2)
{
if ((segtype_is_any_raid10(t1) && !segtype_is_any_raid10(t2)) ||
(!segtype_is_any_raid10(t1) && segtype_is_any_raid10(t2)))
return 0;
return !strncmp(t1->name, t2->name, 5);
}
/*
* HM Helper:
*
* Check for same raid levels in segtype @t1 and @t2
*
* Return 1 if same, else != 1
*/
__attribute__ ((__unused__))
static int is_same_level(const struct segment_type *t1, const struct segment_type *t2)
{
return _cmp_level(t1, t2);
}
/* Return # of reshape LEs per device for @seg */
static uint32_t _reshape_len_per_dev(struct lv_segment *seg)
{
return seg->reshape_len;
}
/* Return # of reshape LEs per @lv (sum of all sub LVs reshape LEs) */
static uint32_t _reshape_len_per_lv(struct logical_volume *lv)
{
struct lv_segment *seg = first_seg(lv);
return _reshape_len_per_dev(seg) * _data_rimages_count(seg, seg->area_count);
}
/*
* HM Helper:
*
* store the allocated reshape length per data image
* in the only segment of the top-level RAID @lv and
* in the first segment of each sub lv.
*/
static int _lv_set_reshape_len(struct logical_volume *lv, uint32_t reshape_len)
{
uint32_t s;
struct lv_segment *data_seg, *seg = first_seg(lv);
if (reshape_len >= lv->le_count - 1)
return_0;
seg->reshape_len = reshape_len;
for (s = 0; s < seg->area_count; s++) {
if (!seg_lv(seg, s))
return_0;
reshape_len = seg->reshape_len;
dm_list_iterate_items(data_seg, &seg_lv(seg, s)->segments) {
data_seg->reshape_len = reshape_len;
reshape_len = 0;
}
}
return 1;
}
/* HM Helper:
*
* correct segments logical start extents in all sub LVs of @lv
* after having reordered any segments in sub LVs e.g. because of
* reshape space (re)allocation.
*/
static int _lv_set_image_lvs_start_les(struct logical_volume *lv)
{
uint32_t le, s;
struct lv_segment *data_seg, *seg = first_seg(lv);
for (s = 0; s < seg->area_count; s++) {
if (!seg_lv(seg, s))
return_0;
le = 0;
dm_list_iterate_items(data_seg, &(seg_lv(seg, s)->segments)) {
data_seg->reshape_len = le ? 0 : seg->reshape_len;
data_seg->le = le;
le += data_seg->len;
}
}
/* Try merging rimage sub LV segments _after_ adjusting start LEs */
for (s = 0; s < seg->area_count; s++)
if (!lv_merge_segments(seg_lv(seg, s)))
return_0;
return 1;
}
/*
* Relocate @out_of_place_les_per_disk from @lv's data images begin <-> end depending on @where
*
* @where:
* alloc_begin: end -> begin
* alloc_end: begin -> end
*/
enum alloc_where { alloc_begin, alloc_end, alloc_anywhere, alloc_none };
static int _lv_relocate_reshape_space(struct logical_volume *lv, enum alloc_where where)
{
uint32_t le, begin, end, s;
struct logical_volume *dlv;
struct dm_list *insert;
struct lv_segment *data_seg, *seg = first_seg(lv);
if (!_reshape_len_per_dev(seg))
return_0;
/*
* Move the reshape LEs of each stripe (i.e. the data image sub lv)
* in the first/last segment(s) across to the opposite end of the
* address space
*/
for (s = 0; s < seg->area_count; s++) {
if (!(dlv = seg_lv(seg, s)))
return_0;
switch (where) {
case alloc_begin:
/* Move to the beginning -> start moving to the beginning from "end - reshape LEs" to end */
begin = dlv->le_count - _reshape_len_per_dev(seg);
end = dlv->le_count;
break;
case alloc_end:
/* Move to the end -> start moving to the end from 0 and end with reshape LEs */
begin = 0;
end = _reshape_len_per_dev(seg);
break;
default:
log_error(INTERNAL_ERROR "bogus reshape space reallocation request [%d]", where);
return 0;
}
/* Ensure segment boundary at begin/end of reshape space */
if (!lv_split_segment(dlv, begin ?: end))
return_0;
/* Select destination to move to (begin/end) */
insert = begin ? dlv->segments.n : &dlv->segments;
if (!(data_seg = find_seg_by_le(dlv, begin)))
return_0;
le = begin;
while (le < end) {
struct dm_list *n = data_seg->list.n;
le += data_seg->len;
dm_list_move(insert, &data_seg->list);
/* If moving to the begin, adjust insertion point so that we don't reverse order */
if (begin)
insert = data_seg->list.n;
data_seg = dm_list_item(n, struct lv_segment);
}
le = 0;
dm_list_iterate_items(data_seg, &dlv->segments) {
data_seg->reshape_len = le ? 0 : _reshape_len_per_dev(seg);
data_seg->le = le;
le += data_seg->len;
}
}
return 1;
}
/*
* Check if we've got out of space reshape
* capacity in @lv and allocate if necessary.
*
* We inquire the targets status interface to retrieve
* the current data_offset and the device size and
* compare that to the size of the component image LV
* to tell if an extension of the LV is needed or
* existing space can just be used,
*
* Three different scenarios need to be covered:
*
* - we have to reshape forwards
* (true for adding disks to a raid set) ->
* add extent to each component image upfront
* or move an existing one at the end across;
* kernel will set component devs data_offset to
* the passed in one and new_data_offset to 0,
* i.e. the data starts at offset 0 after the reshape
*
* - we have to reshape backwards
* (true for removing disks form a raid set) ->
* add extent to each component image by the end
* or use already existing one from a previous reshape;
* kernel will leave the data_offset of each component dev
* at 0 and set new_data_offset to the passed in one,
* i.e. the data will be at offset new_data_offset != 0
* after the reshape
*
* - we are free to reshape either way
* (true for layout changes keeping number of disks) ->
* let the kernel identify free out of place reshape space
* and select the appropriate data_offset and reshape direction
*
* Kernel will always be told to put data offset
* on an extent boundary.
* When we convert to mappings outside MD ones such as linear,
* striped and mirror _and_ data_offset != 0, split the first segment
* and adjust the rest to remove the reshape space.
* If it's at the end, just lv_reduce() and set seg->reshape_len to 0.
*
* Does not write metadata!
*/
static int _lv_alloc_reshape_space(struct logical_volume *lv,
enum alloc_where where,
enum alloc_where *where_it_was,
struct dm_list *allocate_pvs)
{
uint32_t out_of_place_les_per_disk;
uint64_t data_offset;
struct lv_segment *seg = first_seg(lv);
if (!seg->stripe_size)
return_0;
/* Ensure min out-of-place reshape space 1 MiB */
out_of_place_les_per_disk = max(2048U, (unsigned) seg->stripe_size);
out_of_place_les_per_disk = (uint32_t) max(out_of_place_les_per_disk / (unsigned long long) lv->vg->extent_size, 1ULL);
/* Get data_offset and dev_sectors from the kernel */
if (!lv_raid_data_offset(lv, &data_offset)) {
log_error("Can't get data offset and dev size for %s from kernel.",
display_lvname(lv));
return 0;
}
/*
* If we have reshape space allocated and it has to grow,
* relocate it to the end in case kernel says it is at the
* beginning in order to grow the LV.
*/
if (_reshape_len_per_dev(seg)) {
if (out_of_place_les_per_disk > _reshape_len_per_dev(seg)) {
/* Kernel says data is at data_offset > 0 -> relocate reshape space at the begin to the end */
if (data_offset && !_lv_relocate_reshape_space(lv, alloc_end))
return_0;
data_offset = 0;
out_of_place_les_per_disk -= _reshape_len_per_dev(seg);
} else
out_of_place_les_per_disk = 0;
}
/*
* If we don't reshape space allocated extend the LV.
*
* first_seg(lv)->reshape_len (only segment of top level raid LV)
* is accounting for the data rimages so that unchanged
* lv_extend()/lv_reduce() can be used to allocate/free,
* because seg->len etc. still holds the whole size as before
* including the reshape space
*/
if (out_of_place_les_per_disk) {
uint32_t data_rimages = _data_rimages_count(seg, seg->area_count);
uint32_t reshape_len = out_of_place_les_per_disk * data_rimages;
uint32_t prev_rimage_len = _lv_total_rimage_len(lv);
uint64_t lv_size = lv->size;
if (!lv_extend(lv, seg->segtype, data_rimages,
seg->stripe_size, 1, seg->region_size,
reshape_len /* # of reshape LEs to add */,
allocate_pvs, lv->alloc, 0)) {
log_error("Failed to allocate out-of-place reshape space for %s.",
display_lvname(lv));
return 0;
}
lv->size = lv_size;
/* pay attention to lv_extend maybe having allocated more because of layout specific rounding */
if (!_lv_set_reshape_len(lv, _lv_total_rimage_len(lv) - prev_rimage_len))
return 0;
}
/* Preset data offset in case we fail relocating reshape space below */
seg->data_offset = 0;
/*
* Handle reshape space relocation
*/
switch (where) {
case alloc_begin:
/* Kernel says data is at data_offset == 0 -> relocate reshape space at the end to the begin */
if (!data_offset && !_lv_relocate_reshape_space(lv, where))
return_0;
break;
case alloc_end:
/* Kernel says data is at data_offset > 0 -> relocate reshape space at the begin to the end */
if (data_offset && !_lv_relocate_reshape_space(lv, where))
return_0;
break;
case alloc_anywhere:
/* We don't care where the space is, kernel will just toggle data_offset accordingly */
break;
default:
log_error(INTERNAL_ERROR "Bogus reshape space allocation request.");
return 0;
}
if (where_it_was)
*where_it_was = data_offset ? alloc_begin : alloc_end;
/* Inform kernel about the reshape length in sectors */
seg->data_offset = _reshape_len_per_dev(seg) * lv->vg->extent_size;
return _lv_set_image_lvs_start_les(lv);
}
/* Remove any reshape space from the data LVs of @lv */
static int _lv_free_reshape_space_with_status(struct logical_volume *lv, enum alloc_where *where_it_was)
{
uint32_t total_reshape_len;
struct lv_segment *seg = first_seg(lv);
if ((total_reshape_len = _reshape_len_per_lv(lv))) {
enum alloc_where where;
/*
* raid10:
*
* the allocator will have added times #data_copies stripes,
* so we need to lv_reduce() less visible size.
*/
if (seg_is_any_raid10(seg)) {
if (total_reshape_len % seg->data_copies)
return_0;
total_reshape_len /= seg->data_copies;
}
/*
* Got reshape space on request to free it.
*
* If it happens to be at the beginning of
* the data LVs, remap it to the end in order
* to be able to free it via lv_reduce().
*/
if (!_lv_alloc_reshape_space(lv, alloc_end, &where, NULL))
return_0;
seg->extents_copied = first_seg(lv)->area_len;
if (!lv_reduce(lv, total_reshape_len))
return_0;
seg->extents_copied = first_seg(lv)->area_len;
if (!_lv_set_reshape_len(lv, 0))
return 0;
/*
* Only in case reshape space was freed at the beginning,
* which is indicated by "where == alloc_begin",
* tell kernel to adjust data_offsets on raid devices to 0.
*
* The special, unused value '1' for seg->data_offset will cause
* "data_offset 0" to be emitted in the segment line.
*/
seg->data_offset = (where == alloc_begin) ? 1 : 0;
} else if (where_it_was)
*where_it_was = alloc_none;
return 1;
}
__attribute__ ((__unused__))
static int _lv_free_reshape_space(struct logical_volume *lv)
{
return _lv_free_reshape_space_with_status(lv, NULL);
}
/*
* _alloc_rmeta_for_lv
* @lv
@ -4088,12 +4506,6 @@ static takeover_fn_t _get_takeover_fn(const struct lv_segment *seg, const struct
return _takeover_fns[_segtype_ix(seg->segtype, seg->area_count)][_segtype_ix(new_segtype, new_image_count)];
}
/* Number of data (not parity) rimages */
static uint32_t _data_rimages_count(const struct lv_segment *seg, const uint32_t total_rimages)
{
return total_rimages - seg->segtype->parity_devs;
}
/*
* Determine whether data_copies, stripes, stripe_size are
* possible for conversion from seg_from to new_segtype.

2
lib/raid/raid.c
View File

@ -171,7 +171,7 @@ static int _raid_text_import(struct lv_segment *seg,
}
if (seg->data_copies < 2)
seg->data_copies = 0; // lv_raid_data_copies(seg->segtype, seg->area_count);
seg->data_copies = lv_raid_data_copies(seg->segtype, seg->area_count);
if (seg_is_any_raid0(seg))
seg->area_len /= seg->area_count;